Steam and catalytic cracking of hydrocarbons are important processes in the refining and petrochemical industry and is used to produce light olefins such as ethylene, propylene and butadiene from heavier and more complex organic molecules. These light olefins can be used as intermediates to generate other hydrocarbons such as polyethylene. Hydrocarbon cracking involves a cracking reaction of hydrocarbon feedstreams such as ethane or naphtha and can be carried out in tubular reactor systems.
Problems in hydrocarbon cracker reactor systems include the accumulation of hydrocarbon, e.g., coke, within the tubes and coils of the system. Such coke deposits can interfere with heat flow through the tube walls into the stream of reactants, which can result in higher tube metal temperatures and ultimately reaching the limits of the tube metallurgy. Additionally, the coke deposits can interfere with the flow of the reaction mixture due to a reduced tube cross sectional area and can result in higher pressure drops and a reduction in efficiency. This coke buildup can ultimately result in mandatory shutdown of the reactor and production loss.
Hydrocarbon cracker systems are known in the art. For example, European Patent No. EP0564665 discloses the presence of projections in the shape of longitudinal bars or ribs on the walls of hydrocarbon cracking furnace tubes to enlarge the internal surface of the tubes for heat exchange. Korean Patent Application No. KR1076317 discloses the use of hydrocarbon cracking reactor tubes that include indentations on their inner surface walls that project into the interior of the tube. Chinese Patent Application No. CN201770662 discloses the presence of inwardly projecting and axially spiral circular guide grooves on the wall of a cracking furnace tube to create a higher turbulence of the materials flowing through the tube. PCT Patent No. WO2011/013144 discloses a heat exchanger tube that has an inner surface with a plurality of inward projecting indentations that can be used in thermal processing plants and chemical processing units.
There remains a continued need in the art for hydrocarbon cracker systems that efficiently minimize hydrocarbon accumulation. The presently disclosed subject matter provides such significant advantages over currently available systems.